With her thick luscious dark brown hair, she was unsurprisingly voted the celebrity with the most desirable locks earlier this year.

But as a new mother, it appeared even the Duchess of Cambridge can forget to touch up her roots from time to time after she displayed a smattering of grey hairs earlier this month.

The grey hairs were long gone this evening however when Kate attended a charity ball with her dark, wavy locks back to their glossy best.

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The Duchess of Cambridge showed off visibly darker hair when she arrived at the SportsAid SportsBall in London this evening, pictured left, compared to other public appearances earlier this month, pictured right

The Duchess appeared to have had her hair darkened and trimmed in preparation for the event

The Duchess looked her usual immaculate self in an elegant off-the-peg Temperley dress paired with Jimmy Choo shoes at the London event.

But it was her hair that sparked the most interest after apparently having undergone a transformation since her other recent outing.

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Her hair became the focus at a recent Poppy Appeal event in London when she displayed several grey hairs in her centre parting, while her eyes were also perhaps a little shadowed.

Many new mothers, like Kate, find that their hair changes after they give birth.

Greying hair is not normally directly associated with pregnancy, however, any form of stress can encourage it and can be a side effect of being pregnant or giving birth.

Attire: The Duchess's Alice Temperley dress incorporated the best of traditional and modern

She wowed crowds as she walked down the red carpet at the Embankment Gardens in Central London

The spotlight has now turned on her after her husband, Prince William, performed on stage with Jon Bon Jovi earlier this week

Kate's visible grey hairs in recent weeks suggested that the Duchess, like many breastfeeding women, had decided not to dye or highlight her hair.

But tonight her hair appeared significantly darker and more bouncy than it has of late. She also appeared to have had an inch or two trimmed from the length.

Kate, 31, left four-month-old baby
George with daddy at Kensington Palace while she attended the London
SportsAid ball as patron of the charity, which provides financial support
for promising young athletes.

According
to sources Kate normally enhances her sleek hairstyle with an organic
vegetable-based colour wash and subtle low lights at the Richard Ward
salon in Chelsea.

Kate's hair has long been the envy of women around the world.

Her thick mahogany locks that never frizz, kink or wisp have, unsurprisingly, become her trademark.

The Duchess of Cambridge, who left her hair long
and loose, with blonde highlights (and a hint of grey) coming through
the chestnut, rides a 1960s Routemaster bus as part of the London Poppy
Day events

Sources have previously said that the Duchess had, to her horror, started finding the odd
grey hair (‘stress highlights’, her friends joke) before her pregnancy

Kate pulls her hair away from her face and enjoys a laugh as she and Prince William arrive to meet staff and volunteers

In fact, the 'cascading locks' of the former Kate Middleton were voted the celebrity hair other women would most like to have.

Kate's hair was followed closely by the wavy blonde 'elegant and effortless' tresses of Mick Jagger's ex-wife Jerry Hall, and the shiny 'big bouffant' of singer Cheryl Cole.

Model and presenter Kelly Brook, Spice Girl Victoria Beckham and new mum Adele also made it into the top five, while Holly Willoughby just missed out.

The survey, conducted by professional hair product retailer, Fabriah.com, polled 700 of the site's female users and asked them which celebrity hair they would most like to have.

And with Kate's hair back in tip-top shape, it appears she is likely to stay at the top.

This time last year, pictured above, Kate's hair was noticeably darker, and parted at the side